COL2A1 and Kniest dysplasia: A wide spectrum of diseases is associated with COL2A1, including cartilage and bone abnormalities, such as spondyloepimetaphyseal dysplasia, Kniest dysplasia, and early onset osteoarthritis (Kuivaniemi et al., 1991; Löppönen et al., 2004; Wilkin et al., 1999; Xiong et al., 2018).